text: The radiation effects of high cis-1,4-Polybutadiene(NdBR) under UV irradiation were studied by 1D and 2D NMR spectroscopy and X-ray diffraction.The results indicated that the oxidation reaction taken place more easily at the doble bond terminated in the main chain than in the side vinyl group terminated of polybutadiene with the increase of UV irradiation time.Moreover,the sample halfwidth increased,it indicated that the sample occurs crosslinking reaction in the processing of irradiation.The data from X-ray diffraction showed that the crystallization peak intensity of the sample was decreased with UV irradiation time increase.This indicated that the crystal content of the sample are down after UV irradiation.